I would like to put a RB exhaust system on my stock 85 GS 12A with manual trans. I will in the future most likely change carb to high performance carb (still not sure which one, leaning towards a "fat Nikki"). Anyway which exhaust would you recommend; Street port or long primary system? And why? Not planning to port the motor anytime soon, only has 35K on it. I am ok with increased noise as long as not insanely loud and does not drone while driving on interstate.

 

long primary. top end power is about the same, but the long primary system makes more low end.

 

Long primary makes more power everywhere. It also doesn't drone.

 

Everyone here seems to recommend the long primaries, sadly I went with the short before I knew. I wish I would have done the research. Either way, it was a big increase in power over stock! I also have a Magnaflow muffler on the end so it is loud with a lot of drone. Do I regret it? when I am on long trips yes, because my ears start to hurt a little from drone, but when I am not on long trips, no I do not!

However I have never driven a car with long primaries from RB.

 

You want the RB SP (long primary) exhaust system. Get the whole thing from header to muffler,
don't skimp and it will have a great sound, execellent low end response and can be used
unchanged with any other intake or ignition changes you have planned in the future.

BTW, a fat nikki is a really cost effective way to get fantastic performance out of your stock port
12A. You can't go wrong with it.

 

How loud/quiet is that system?